Compounded turbine oil



United States COMPOUNDED TURBINE OIL Troy L. Cantrell, Drexel Hill, Pa.,and John G. Peters, A udubon, N. .L, assignors to Gulf Oil Corporation,Pittsburgh, Pa., a corporation of Pennsylvania NoDrawing. ApplicationAugust 19, 1954,

- Serial No. 451,041

oxidation but they have not given complete protection against rustingand corrosion of metal turbine parts which are exposed to moisture.

The present invention is based upon a particularly effective lubricatingcomposition having good resistance to oxidation combined with goodlubricating characteris-' tics, and corrosion and rust-inhibitingproperties.

The improved lubricating composition of this invention consistsessentially of a homogeneous mixture of lu bricating oil, a metal alkylthiophosphate, an alkyl phenol and a substantially neutral additionproduct of isoamyl octyl acid phosphate with primary fatty aminescontain- 111g from '8 'to 18 carbon atoms. We have found that the threeaddition agents just mentioned cooperate to give a composition havingexcellent resistance to oxygen absorption and increased oxidation life.Furthermore the composltion has good corrosion and rust-inhibitingproperties. These rust-inhibiting properties are unexpected in view ofthe performance of the individual additives and of combinations of onlytwo of the additives.

The lubricating oil to which the other constituents are added isadvantageously a highly refined paraflinic oil. By the term highlyrefined paraflinic oil we mean a petroleum lubricating oil which hasbeen refined by one of the more drastic refining methods known in theart, for example, by conventional aluminum chloride refinmg or by asolvent extraction adapted to remove all or substantially all of theunsaturated and naphthenic constituents of the oil. Aluminum chloriderefined or solvent extracted parafiinic base oil, such as a Pennsylvaniaoil, provides an excellent base oil for the composition of theinvention. However, drastically refined Mid-Continent and Gulf Coastaloil may also be used.

The metal alkyl thiophosphates which can be used in. accordance with theinvention are advantageously those whose metal component is a metal ofgroup II of Mend'e-- leeifs periodic arrangement of the elements.Included within this group are magnesium, calcium, zinc, strontium,cadmium and barium. However, other metals including aluminum, copper,lead, tin, iron and manganese can also be employed. The alkylsubstituents are preferably those containing between 3 and 12 carbonatoms.

Examples of the alkyl groups which can be used are butyl,. particularlytertiary butyl, amyl, isoamyl, tertiary amyl,

hexyl, heptyl, octyl, nonyl, decyl, dodecyl and the like.

While the mono-alkyl esters can be used, the di-alkyl esters areparticularly suitable for the purposes of the in- An example of aparticularly effective com- 2,789,952 Patented Apr. .23, 1957 used in anamount between about 0.01 and 0.1 percent by weight based on the weightof the total composition. An amount greater than about 0.1 percent isundesirable in that the neutralization number of the final product isincreased above the maximum set for commercial use.

The alkyl phenol which is used in accordance with the invention isadvantageously a dior trialkylated phenol or cresol with at least one ofthe alkyl groups being a tertiary alkyl group. The alkyl groups arepreferably those containing between 3 and 12 carbon atoms. Good resultscan be obtained with a tri-tertiary butyl phenol or a di-tertiary butylcresol. Examples of the preferred alkylated phenols are2,4,G-tri-tertiary-butylphenol, 2,6- di-tertiary-butyl-4-methylphenoland bis(2 hydroxy 3- tertiary-butyl-S-methylphenyl)methane. The alkylphenols are advantageously used in amounts of about 0.1 to about 2.0percent by weight based on the weight of the total composition.

The fatty amine salt of isoamyl octyl acid phosphate which can be usedin accordance with the invention is prepared by reacting isoamyl octylacid phosphate with a primary fatty amine containing from 8 to 18 carbonatoms. One example of a primary fatty amine suitable for the purpose ofthis invention is cocoamine, which is a commercially available productprepared by converting coconut oil fatty acids into the correspondingamine. It consists mostly of monolauryl amine with minor amounts ofadjacent homologues. The cocoamine salt of isoamyl octyl acid phosphateand its preparation are fully described in U. S. Patent No. 2,371,851which issued on March 20, 1945 to Herschel G. Smith and Troy L.Cantrell. As disclosed in said patent, the cocoamine salt of isoamyloctyl acid phosphate can be readily prepared by reacting cocoamine withisoamyl octyl acid phosphate in approximately equimolecular ratios, thereaction being so controlled as to produce substantially neutralreaction mixtures having a pH value within the range 5.5 to 7.5, asillustrated in Examples 1 and 2 of that patent. The isoamyl octyl acidphosphate employed is a di-ester of orthophosphoric acid having thefollowing formula:

HHH 0 EH This compound is also known as 3-methylbutyl, Z-ethylhexyl acidorthophosphate. It readily reacts with cocoamine and other primary fattyamines containing from 8 to 18 carbon atoms. Instead of cocoamine we canuse other primary fatty amines containing from 8 to 18 car- .bon atoms.These amines include mono-capryl,

CH3 (CH2) sCHzNHz .mono-lauryl, mono-myristyl, mono-palmityl andmonostearyl amines. The fatty acid amine salt of isoamyl octyl acidphosphate is preferably used in an amount beoiveen about 0.01 and about1.0 percent by weight based on the weight of the total composition.

The lubricating oil compositions of this invention can contain otheradditive agents, if desired, to improve other specific propertieswithout deleteriously affecting the beneficial properties of thecompositions. For example, pour point depressors, viscosity andviscosity index improvers, dyes, sludge inhibitors and the like can beused. Also, if desired, the oil can contain a foam inhibitor such asorgano-silicon oxide condensation products, organo-silicol condensationproducts, and the like.

The individual constituents of compositions of this invention may beadded to the lubricating oil base in either order or simultaneously,either per se, or in the form of a mineral oil concentrate. The latterpractice is sum;-

times desirable in order to facilitate compounding of the lubricatingoil.

0.0033 percent by weight of Dow-Corning silicone fluid '200 as a foaminhibitor. The results were as follows:

Composition, percent byswt .Baseoil 2, 'o-ditertiary-buryl-4-ruethylphenol Zincdihexyh thiophosphate Cocoamiue.isoamyl-octyl .orthophosphate Amount of rust, ASTM D 1943 T. 500

.huurs, iron coil.

Heavy rust.

Heavy rust Heavy rust..

.Heavy rust" The 1 advantages obtained .by.' the use of the improvedlubricating: composition of the invention as compareiwith theme ofsimilar. compositions containingionly: one or two' of theithreeaddition:agents are illustrated in; the following specifi'c examples.lheefiectiveness'of the. rustinhibitingzproperties has beenidemonstratedby isnbjecting ithe lubricating. compositions to the-procedure ofASTMItestD 9434'7 vT. Briefly, this 'testxiscarried out by passingoxygenat a measured rate of-3 liters'perhour into an oil-water mixturemaintained at 203 P. and having an iron coil immersed therein. Accordingto the procedure followed herein, the test was carried out for 500hours. The corrosion-inhibiting properties of the compositions weredetermined by examining the iron coil before and after completion of thetest. The amount of rust on the coil was thus used to determine theeffectiveness ofthe composition in preventing rust.

Tov illustrate the'rust-inhibiting properties of the com position of theinvention as compared with similar compositions containing only one ortwo of the addition agents, samples of the oils were subjected to theabovedescribed ASTM test D 943-47 T. The base oil used in the test was ahighly refined, aluminum chloride treated, paraifinic turbine oil stockhaving an API gravity between about 30.5 and 325 and a viscosity ofabout 150 SUS at 100 F. In each instance the oil. also contained As canhe noted from theabove data, a composition of the invention, compositionE, is strikingly superior to compositions not within the scope of theinvention. The synergistic effect obtained issh'own inasmuch as theindividual additives and a combination of only two of the additives didnot give the improved result obtained by a combination of all threeofthe additives.

While the invention has been described above with reference tocertainspecific embodiments thereof by Way of illustration, it is to beunderstood that the invention is not limited to such embodiments exceptas hereinafter defined in the appended claim.

We claim:

A inst-inhibiting oil consisting essentially of a major proportion of amineral lubricating oil and minor proportions consisting of about 0.1 toabout 2.0 percent by weight of 2,6-di-tertiary-butyl-4-methylpheno1,about 0.01 to about10.l percent by weight of zinc dihexyl thiophosphateand about 0.01 to about 1.0 percent by weight of the cocoalfillne saltof 3-methylbutyl,2-ethy1hexy1 acid orthophosp ate.

Freuler Dec. 5, 1944 Smith et a1 Mar. 20, 1945

